Resilient wheel

ABSTRACT

A wheel in which the load bearing portion adapted to engage the ground is essentially in the form of a multiplicity of spring convolutions. In a preferred form these convolutions form parts of a continuous helically coiled spring bent to extend around the periphery of the central portion of the wheel.

United States Patent 91 Hawes RESILIENT WHEEL [76] Inventor: Edward M.Hawes, 32418 Birkshire,

St. Clair Shores, Mich. 48082 [22] Filed: Dec. 23, 1971 [21] Appl. No.:211,589

5/1907 Krell 152/92 7/1966 Stanley 152/92 Primary ExaminerJames B.Marbert Attorney-Donald P. Bush [57] ABSTRACT A wheel in which the loadbearing portion adapted to engage the ground is essentially in the formof a multiplicity of spring convolutions. In a preferred form theseconvolutions form parts of a continuous helically coiled spring bent toextend around the periphery of the central portion of the wheel.

14 Claims, 7 Drawing Figures PATENTEU Um 91975 FIGZ 1 RESILIENT WHEELBRIEF SUMMARY OF THE INVENTION The present invention relates to a wheelintended generally for use on sand, loose dirt, mud, or other similarterrain.

In its simplest form the invention comprises a wheel having a circularcentral portion and provided with a tread or ground engaging loadsupporting surface in the form of a multiplicity of spring convolutions.Conveniently, these spring convolutions may be provided by bendingahelically coiled spring around the periphery of the wheel in theposition normally occupied by the tire.

Since the spring convolutions at the outer periphery of the wheel arespaced apart they become embedded into the loose material of the terrainwhich therefore enters into the annular space defined by the completeseries of convolutions. In a preferred form of the invention thesupporting wheel is provided with a tapered peripheral portion whichextends substantially into the annular space defined by the completeseries of spring convolutions, the radially inwardly diverging sidesserving to guide the material forced into the spring assembly by groundpressure outwardly as the wheel turns, thus tending to keep the interiorof the spring or the annular space defined by the spring, substantiallyclear of ground material.

Preferably, means are provided extending around the spring assemblytending to maintain the adjacent convolutions against individualcircumferential displacement so as to maintain the designed spacingtherebetween under service conditions. In addition, the convolutions maybe designed to define a substantially cylindrical outer surface which inturn establishes a great area of contact with the ground, and further,reduces excessive wear centrally of the spring convolutions.

In some cases it is desirable to cover the outer peripheral envelopedefined by the spring convolutions with a relatively coarse screenmaterial, whichwill contribute to support 'of the spring structure insand, soft ground, mud, or the like. 7

Finally, traction may be increased by providing transversely extendingground engaging cleats.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary more or lessdiagrammatic elevational view of a wheel assembly constructed inaccordance with the present invention.

FIG. 2 is a fragmentary sectional view on the line 2-2, FIG. 1.

FIG. 3 is a fragmentary elevational view of another embodiment of theinvention, with parts broken away.

FIG. 4 is a sectional view on the line 44, FIG. 3.

FIG. 5 is a side elevational view of a wheel assembly representing afurther embodiment of the present invention.

FIG. 6 is a fragmentary elevational view illustrating the application ofcleats to the tread structure.

FIG. 7 is a fragmentary end view of the structure shown in FIG. 6.

DETAILED DESCRIPTION Referring first to FIGS. 1 and 2, the centralportion of the wheel assembly is indicated diagrammatically at 10 as agenerally circular block having a peripheral arcuate groove 12 extendingtherearound. It will of course be understood that in practice the wheelproper will be provided with the usual structure permitting itsattachment to rotatable wheel supporting structure, but

this forms no part of the present invention and is omitinner portions 16of the convolutions are brought towards each other. As illustrated inFIG. I, the inner portions 16 of the convolutions may be brought intoactually circumferential engagement or alternatively, they may remainslightly spaced apart. In any case, due to the curvature of the coilspring into a circular shape, the outer portions of the springconvolutions as indicated at 20 are moved apart to a separation greaterthan occurs in the straight helical spring.

Any suitable means may be provided for establishing a permanentconnection between the inner convolution portion 16 and the interfittingcorrugated surface of the wheel 10. For example, the individualconvolutions may be welded or brazed in place. Alternatively, amechanically engaging mounting ring indicated at 22 may extend aroundand engage the inner surfaces of the inner convolution portions 16. Thering 22 may have end structure adapted to overlap and to receive cammingmeans effective to tighten the ring so as to press the innerconvolutions of the spring into the corrugations 14. The structureillustrated in FIGS. 1 and 2 includes a multiplicity ofcircumferentially extending rings 24 which as shown are interlaced backand forth between adjacent convolutions, the adjacent rings 24 beingdisposed at opposite sides of each particular convolution, as bestillustrated in FIG. .1. Again, the rings 24 may be permanently attachedto the spring convolution in the position shown by suitable means suchfor example as welding, brazing, or the like.

The individual spring convolutions, as best seen in FIG. 2, arepreferably not completely circular, but each includes a radially outerstraight portion 26 adapted to have theoretical contact from end to endwith the terrain when the structure is employed in supporting a vehicle.It will be appreciated that the complete envelope described by themultiplicity of straight convolution portions 26 is essentiallycylindrical.

As best seen in the Figures, the extreme outer periphery of the springtire assembly is provided with a relatively coarse screen structure 30which in turn may be attached to the straight convolution portions 26 bysuitable means such for example as welding, brazing or the like.

With the structure as above described, it will be apparent that whensupporting a vehicle, and particularly a heavy vehicle, on soft terrainsuch as sand, loose dirt, mud or the like, the resilient wheel iscapable of supporting the load, and due to the tying together ofadjacent spring convolutions, the load will be distributed over amultiplicity of convolutions without permitting displacement ofindividual spring convolutions. The amount of penetration of theresilient wheel assembly into the terrain may be controlled bydimensions of the parts, particularly the coarseness of the screen 30where such screen is provided.

In the simplest possible case the spring convolutions may be completelycircular and the tying rings 24 and the screen 30 may be omitted.Alternatively, the tying rings 24 may be provided and the screen 30omitted, or the screeen may be provided and the tying ring 24 omitted,in which case the screen serves the dual function of controllingpenetration and also tying adjacent convolutions together to preventlateral displacement of individual convolutions.

The resilient wheel structure provided by bending the helically coiledspring into a circular or annular configuration, supported on theperiphery of the inner wheel portion, also provides great stabilityagainst lateral displacement, particularly when the inner portion of thespring assembly is received in an annular channel of arcuatecross-section, as best illustrated in FIG. 2.

Referring now to FIGS. 3 and 4 there is illustrated a further embodimentof the present invention. In this case the inner wheel portion indicatedgenerally at 34, is composed of two circular or preferably annularelements 36 and 38 which are brought together in assembly and united toform a unitary structure. The peripheral portions 40 of the rings 36 and38 are tapered and are slotted, the bottoms of the slots as indicated at42 being of arcuate cross-section so as to receive and closely interfitwith the inner portions 44 of the spring convolutions 46. With thisarrangement the inner convolution portions 46 are fully supportedagainst circumferential movement by the material 48 intermediate anddefining the slots 50 which receive the individual spring convolutions.In assembly, the coil spring may be bent into the circular configurationshown and the two wheel portions 36 and 38 assembled by movement towardeach other into the position illustrated in FIG. 4. The ends of thehelically coiled spring may be united by suitable means such for exampleas welding, or by reception in a tubular connecting element (not shown).

As best seen in FIG. 4 the slots 50 are radial and are of a uniformwidth such as to receive the wire of the convolutions of the spring. Asa result, the material 48 intermediate adjacent convolutions is taperedand of outwardly increasing circumferential dimension.

As best seen in FIG. 3, the convolutions 46 of the spring may be fullycircular although it is also contemplated that they may be straightacross their outer peripheral portion in the same manner as the straightportions 26 of the spring shown in FIG. 2. Again, the convolutions areinterconnected by rings indicated at 52 which are preferably interleavedintermittently inwardly and outwardly of the convolutions, as bestillustrated in FIG. 3. As indicated in these Figures, three rings areprovided at each side of the resilient wheel assembly and a single ring54 is provided centrally of the wheel at its outer periphery.

The construction illustrated in FIGS. 3 and 4 provides the radiallyoutwardly extending tapered wheel portion indicated in its entirety at56 which extends substantially into the hollow interior of the resilientspring tire support structure. This wheel portion 56 serves to guidematerial penetrating into the hollow interior 58 of the assemblylaterally as the wheel turns so as to provide for expulsion of loosematerial such as sand or dirt which is forced into the interior 58 byground pressure as the vehicle moves over the terrain.

While in FIGS. 3 and 4, no screen such as the screen 30 of FIGS. 1 and 2is illustrated, it will of course be appreciated that if desired screenmaterial of this type may be applied over the outer transversely curvedperipheral surface of the resilient wheel assembly.

FIG. 5 is a side elevation ofa wheel somewhat similar to that shown inFIG. 2, in which the convolutions of the main wheel supporting structureare indicated at 60 and are interleaved with annular wire rings'62substantially similar to the rings 52 disclosed in FIG. 3, and the rings24 disclosed in FIG. 1. In this case the radially outer portion of eachconvolution is relatively straight as indicated at 64 so as to provide asubstantially cylindrical envelope 66, of the general configurationillustrated in FIG. 2. In this case however, the generally flatconvolution portions are interlaced with circumferentially extendingrings 68 which are provided in over and under relation to define thegenerally recticulate form best illustrated at 70. In many cases thiswill be the final condition of the wheel assembly although it iscontemplated that if desired a relatively coarse screen as indicated at72, may be provided to overlie the interlaced spring convolutions, andcircular tie rings 68. This will in general be a matter of choicedepending upon the terrain for which the resilient wheel is designed.

Referring to FIGS. 6 and 7 there is illustrated a further modificationwhich may be applied generally to any of the wheel previously described.In these Figures the wheels are illustrated as supplied around theirouter periphery with the screen material 76 and to provide for increasedtraction transversely extending cleats 78 are provided with may beattached by any suitable means such for example as rivets or threadedfasteners indicated diagrammatically at 80. While in FIGS. 6 and 7 thetransversely extending cleats are indicated as straight and as appliedto the cylindrical outer wheel surface such as illustrated in FIGS. 2and 5, it will be appreciated that the cleats may be arcuately curved ifdesired and applied to the outer transversely curved surface of thewheel such as the wheel illustrated in FIGS. 3 and 4, particularly whensupplied with screen material thereover.

The resilient spring structure provided at the periphery of the wheelassembly is not only effective to support the load and to providetraction, but it is effective to withstand the tangential force appliedwhen the wheels provided with the resilient spring portions at theperiphery are driving wheels. This function is enhanced where adjacentconvolutions are interconnected by the tie rings illustrated in theseveral embodiments of the invention.

Conveniently, the springs employed to provide the adjacent springconvolutions may be formed from spring wire of circular cross-sectionsuitably compounded and tempered to produce adequate wear resistance,resilience, and strength to withstand the anticipated loads due to theweight of the vehicle, tangential force applied in driving the wheels,and lateral and other forces applied as a result of turning of thevehicle and/or turning of the wheels relative to the vehicle as insteering.

In all cases, the outer portions of the convolutions provide an annularseries of circumferentially spaced generally transversely extendingresilient supporting ground engaging elements.

What I claim as my invention is:

l. A resilient vehicle wheel assembly comprising a rigid central wheelportion, and a ground engaging load sustaining drive transmittingresilient portion in the form of a series of circumferentially spacedspring wire convolutions extending around the periphery of the assemblyand providing an annular series of circumferentially spaced, generallytransversely extending, resiliently supported ground engaging elements.

2. An assembly as defined in claim 1 in which said convolutions areparts of a helically coiled wire spring bent into overall annular shape.

3. An assembly as defined in claim 2 comprising in addition meanssecuring the radially inner portions of each convolution to the outerperiphery of the central wheel portion.

4. An assembly as defined in claim 3 in which the periphery of thecentral wheel portion is slotted to leave radially outwardly extendingfingers intermediate the slots, said fingers being shaped to assist inexpelling ground material forced into the interior annular space definedby said spring convolutions.

5. An assembly as defined in claim 1 comprising in addition annularmeans connected to each convolution to form tie supports preventingrelative circumferential displacement between adjacent convolutions.

6. An assembly as defined in claim 5 in which said annular meanscomprises wires connected to the side portions of said convolutions.

7. An assembly as defined in claim 6 in which said wires are disposed inalternate inside and outside relation with the series of springconvolutions.

8. An assembly as defined in claim 7 which comprises in addition ascreen tread portion secured around the outer periphery of the assembly.

'9. An assembly as defined in claim 5 in which said annular meanscomprises a screen tread portion secured around the outer periphery ofthe assembly.

10. An assembly as defined in claim 9 comprising in addition amultiplicity of separate transversely extending cleats secured to theperipheral portion of said assembly outwardly of the screen treadportions.

11. A group engaging vehicle wheel for use on soft loose terrain such asloose sand, soil, and the like comprising a rigid rim, a multiplicity ofresilient support elements extending outwardly from both edges of saidrim, said elements being curved to present outwardly convex surfaces atboth sides of said wheel, and an outer ground engaging tread portioncomprising a multiplicity of elongated circumferentially spaced treadelements operatively connected to and supported by said supportelements.

12. A wheel as defined in claim 11 wherein the spacing between adjacenttread elements is greater than the width of said tread elements measuredin a circumferential direction.

13. A wheel as defined in claim 11 in which said ground engaging treadportion comprises a multiplicity of elongated spaced tread elementsextending at an angle to said first mentioned tread elements, andconnected thereto to form therewith an open mesh structure havingopenings through which particulate terrain material may pass.

14. A vehicle wheel assembly for use on soft loose terrain such as sand,soil, and the like comprising a rigid rim, a ground engaging drivetransmitting tread portion including a series of circumferentiallyspaced spring wire elements, and means connecting said tread portion tosaid rim and resiliently supporting said tread portion in spacedsurrounding relation to said rim.

1. A resilient vehicle wheel assembly comprising a rigid central wheelportion, and a ground engaging load sustaining drive transmittingresilient portion in the form of a series of circumferentially spacedspring wire convolutions extending around the periphery of the assemblyand providing an annular series of circumferentially spaced, generallytransversely extending, resiliently supported ground engaging elements.2. An assembly as defined in claim 1 in which said convolutions areparts of a helically coiled wire spring bent into overall annular shape.3. An assembly as defined in claim 2 comprising in addition meanssecuring the radially inner portions of each convolution to the outerperiphery of the central wheel portion.
 4. An assembly as defined inclaim 3 in which the periphery of the central wheel portion is slottedto leave radially outwardly extending fingers intermediate the slots,said fingers being shaped to assist in expelling ground material forcedinto the interior annular space defined by said spring convolutions. 5.An assembly as defined in claim 1 comprising in addition annular meansconnected to each convolution to form tie supports preventing relativecircumferential displacement between adjacent convolutions.
 6. Anassembly as defined in claim 5 in which said annular means compriseswires connected to the side portions of said convolutions.
 7. Anassembly as defined in claim 6 in which said wires are disposed inalternate inside and outside relation with the series of springconvolutions.
 8. An assembly as defined in claim 7 which comprises inaddition a screen tread portion secured around the outer peripheRy ofthe assembly.
 9. An assembly as defined in claim 5 in which said annularmeans comprises a screen tread portion secured around the outerperiphery of the assembly.
 10. An assembly as defined in claim 9comprising in addition a multiplicity of separate transversely extendingcleats secured to the peripheral portion of said assembly outwardly ofthe screen tread portions.
 11. A group engaging vehicle wheel for use onsoft loose terrain such as loose sand, soil, and the like comprising arigid rim, a multiplicity of resilient support elements extendingoutwardly from both edges of said rim, said elements being curved topresent outwardly convex surfaces at both sides of said wheel, and anouter ground engaging tread portion comprising a multiplicity ofelongated circumferentially spaced tread elements operatively connectedto and supported by said support elements.
 12. A wheel as defined inclaim 11 wherein the spacing between adjacent tread elements is greaterthan the width of said tread elements measured in a circumferentialdirection.
 13. A wheel as defined in claim 11 in which said groundengaging tread portion comprises a multiplicity of elongated spacedtread elements extending at an angle to said first mentioned treadelements, and connected thereto to form therewith an open mesh structurehaving openings through which particulate terrain material may pass. 14.A vehicle wheel assembly for use on soft loose terrain such as sand,soil, and the like comprising a rigid rim, a ground engaging drivetransmitting tread portion including a series of circumferentiallyspaced spring wire elements, and means connecting said tread portion tosaid rim and resiliently supporting said tread portion in spacedsurrounding relation to said rim.